A 64-year-old man presents with a 3-month history of fatigue, 6 kg weight loss, new onset headache, scalp tenderness, and jaw claudication. ESR is 88 mm/h. Fundoscopy is normal. Which investigation is now recommended FIRST before initiating treatment, according to ACR/EULAR 2021 guidelines?

• A Start high-dose prednisolone immediately without biopsy
• B MRI brain with gadolinium
• C PET-CT to detect large vessel involvement
• D Temporal artery biopsy or ultrasound of temporal arteries ✓

Explanation

ACR/EULAR 2021 classification criteria and clinical practice guidelines recommend biopsy of the temporal artery (or colour duplex ultrasound showing the characteristic 'halo sign') as the first investigation in suspected GCA to confirm diagnosis before committing to long-term steroid therapy. High-dose steroids should not be delayed if vision is threatened; biopsy remains positive for 2–4 weeks after starting treatment. Ultrasound is now recommended as the initial modality in centres with expertise.

Reference: Harrison's Principles of Internal Medicine, 21st ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.